A fire that has engulfed the historic Notre Dame Cathedral in Paris has shocked people across the world.

The blaze which unfolded on Monday, April 15, was extinguished 15 hours after it first started and caused significant damage to the 850-year-old church, according to CNN. Pictures unveiled on Tuesday show damages include a complete collapse of the roof and the spire of the building. The main structure and two towers remained standing.

In an interview with Associated Press, Bertrand de Feydeau, vice president of preservation company, Fondation du Patrimoine, said the roof can’t be remade because “we don’t at the moment, have trees on our territory of the size that were cut in the 13th century.”

According to CBS, the cause of the fire is unclear, but an investigation involving 50 people is underway. Officials do not suspect terrorism or arson.

The Paris Fire Service said the fire may be due to the renovation work that was underway in the cathedral before the fire started. Just a week before the incident, workers had removed thousands of priceless artifacts from the church, in preparation for the renovation, as reported by CNN.

In his national address, French president Emmanuel Macron assured citizens that Notre Dame would be rebuilt “more beautiful than ever” and he hoped it would be completed in 5 years.

Donations from around the world are rushing in for the repairs. According to People, $1 billion has been raised in two days for the building’s reconstruction.